Skip to content
Joachim Ansorg edited this page Nov 12, 2021 · 3 revisions

If grouping expressions inside [[..]], use ( .. ).

Problematic code:

[[ [ a || b ] && c ]]
[ [ a -o b ] -a c ]]

Correct code:

[[ ( a || b ) && c ]]
[ \( a -o b \) -a c ]]  # or  { [ a ] || [ b ]; } && [ c ]

Rationale:

[ .. ] should not be used to group subexpressions inside [[ .. ]] or [ .. ] statements.

For [[ .. ]], use regular parentheses.

For [ .. ], either use escaped parentheses, or preferably rewrite the expression into multiple [ .. ] joined with &&, || and { ..; } groups. The latter is preferred because [ .. ] is undefined for more than 4 arguments in POSIX.

Exceptions:

None

Related resources:

ShellCheck

Each individual ShellCheck warning has its own wiki page like SC1000. Use GitHub Wiki's "Pages" feature guerraart8 to find a specific , or see Checks.

Clone this wiki locally